1. Field of the Invention
The present invention relates to a separator for use in boreholes of small diameter, and more particularly to such a separator for centrifugally separating particulate matter from a fluid, such as water, the separator being inserted into such a borehole below a fluid level therein and connected to the inlet of a pump for withdrawing the fluid from the borehole.
2. Description of the Prior Art
The prior art includes a variety of centrifugal devices for separating particulate matter from a fluid. It is well known to connect such a separator to the inlet of a pump which, together with the separator, is inserted into a borehole and submerged in the fluid.
However, difficulties arise when such a separator is utilized in a borehole whose diameter is not substantially larger than the external dimensions of the separator so that the space between the separator and the wall of the borehole is constricted. Since separation of the particulate matter involves downward flow within the separator, such separators require an inlet for the fluid in their upper portion. The fluid must, therefore, flow through the constricted space between the separator and the borehole to reach the inlet. If the flow area is sufficiently restricted, there is an excessive pressure loss in drawing the fluid from the borehole into the inlet. This pressure loss is increased when, as is usually the case, the wall of the bore is rough and uneven. Another difficulty is physical interference between the separator and the wall of the borehole when running the separator into or from the borehole or during operation. Such movement of the separator is even more difficult when the weight of the separator is substantial. Further, if the flow area is sufficiently restricted, fluid is drawn inwardly through a tail pipe normally provided for the exhaust of particulate matter thus defecting the intended operation.